cytochrome-c-t and ruboxistaurin

Cardiac dysfunction caused by excessive alcohol consumption is a specific disease, alcoholic cardiomyopathy (ACM). High-dose alcohol has been found to induce oxidation stress and apoptosis in cardiomyocytes, but the signaling link between alcohol-induced oxidation stress and apoptosis in cardiomyocytes remains to be elucidated. To address the issue, we exposed primary cardiomyocytes from neonatal mouse hearts to high doses of alcohol (50mM, 100mM, and 200 mM). We found that alcohol induced dose-dependent phosphorylation of p66shc, and reactive oxygen species (ROS) production increased in parallel with phosphorylation levels of p66shc. Exposure to alcohol also led to loss of mitochondrial membrane potential and cytochrome c release. Depletion of p66Shc and inhibition of protein kinase C-β (PKC-β) successfully reversed all the effects and suppressed alcohol-induced apoptosis in cardiomyocytes. Collectively, our study provides a molecular basis for signaling transduction of alcohol-induced oxidation stress and apoptosis of cardiomyocytes, which may facilitate the prevention and treatment of ACM.

Topics: Animals; Apoptosis; Cardiomyopathy, Alcoholic; Cytochromes c; Enzyme Inhibitors; Ethanol; Indoles; Maleimides; Membrane Potential, Mitochondrial; Mice; Myocytes, Cardiac; Oxidative Stress; Phosphorylation; Protein Kinase C beta; Reactive Oxygen Species; RNA, Small Interfering; Shc Signaling Adaptor Proteins; Signal Transduction; Src Homology 2 Domain-Containing, Transforming Protein 1

Intestinal ischemia-reperfusion (I/R) is a serious clinical dilemma with high morbidity and mortality. Remote organ damage, especially acute lung injury and liver injury are common complications that contribute to the high mortality rate. We previously demonstrated that activation of PKCβII is specifically involved in the primary injury of intestinal I/R. Considering the tissue-specific features of PKC activation, we hypothesized that some kind of PKC isoform may play important roles in the progression of secondary injury in the remote organ. Mice were studied in in vivo model of intestinal I/R. The activation of PKC isoforms were screened in the lung and liver. Interestingly, we found that PKCβII was also activated exclusively in the lung and liver after intestinal I/R. PKCβII suppression by a specific inhibitor, LY333531, significantly attenuated I/R-induced histologic damage, inflammatory cell infiltration, oxidative stress, and apoptosis in these organs, and also alleviated systemic inflammation. In addition, LY333531 markedly restrained p66shc activation, mitochondrial translocation, and binding to cytochrome-c. These resulted in the decrease of cytochrome-c release and caspase-3 cleavage, and an increase in glutathione and glutathione peroxidase. These data indicated that activated PKC isoform in the remote organ, specifically PKCβII, is the same as that in the intestine after intestinal I/R. PKCβII suppression protects against remote organ injury, which may be partially attributed to the p66shc-cytochrome-c axis. Combined with our previous study, the development of a specific inhibitor for prophylaxis against intestinal I/R is promising, to prevent multiple organ injury.

Topics: Animals; Apoptosis; Caspase 3; Cytochromes c; Glutathione; Indoles; Intestines; Liver; Lung; Male; Maleimides; Mice, Inbred ICR; Mitochondria; Protective Agents; Protein Kinase C beta; Protein Kinase Inhibitors; Reperfusion Injury; Shc Signaling Adaptor Proteins; Signal Transduction; Src Homology 2 Domain-Containing, Transforming Protein 1